Aaron DeLonay
Science and Products
Comprehensive Sturgeon Research Project Blog - 2018
The USGS Comprehensive Sturgeon Research Project is a multi-year, interdisciplinary research study to determine factors leading to spawning and survival of the endangered pallid sturgeon and the closely related shovelnose sturgeon.
Comprehensive Sturgeon Research Project Blog - 2020
The USGS Comprehensive Sturgeon Research Project is a multi-year, interdisciplinary research study to determine factors leading to spawning and survival of the endangered pallid sturgeon and the closely related shovelnose sturgeon.
Comprehensive Sturgeon Research Project Blog - 2019
The USGS Comprehensive Sturgeon Research Project is a multi-year, interdisciplinary research study to determine factors leading to spawning and survival of the endangered pallid sturgeon and the closely related shovelnose sturgeon.
Pallid Sturgeon Early Life
CERC biologists focus on improving understanding of biomechanics of eggs, free embryos, and larvae through direct observation and measurement. An improved understanding of biomechanics – how biotic conditions and processes interact with physical processes to result in changes in survival – is necessary to create quantitative links between management actions and population-level results.
Adult Pallid Sturgeon Reproductive Ecology
CERC fish biologists study migrations, reproductive cues, and spawning behaviors of reproductive wild and hatchery-origin pallid sturgeon (HOPS) in the Missouri River Basin.
Comprehensive Sturgeon Research Project Blog - 2016
The USGS Comprehensive Sturgeon Research Project is a multi-year, interdisciplinary research study to determine factors leading to spawning and survival of the endangered pallid sturgeon and the closely related shovelnose sturgeon.
Comprehensive Sturgeon Research Project (CSRP)
The Comprehensive Sturgeon Research Project (CSRP) is a multidisciplinary project conducted in cooperation with the U.S. Army Corps of Engineers, Missouri River Recovery Program–Integrated Science Program. CERC scientists are working with river scientists and managers to develop methods, baseline information, and research approaches that are critical contributions to recovery success of the...
Comprehensive Sturgeon Research Project Blog - 2017
The USGS Comprehensive Sturgeon Research Project is a multi-year, interdisciplinary research study to determine factors leading to spawning and survival of the endangered pallid sturgeon and the closely related shovelnose sturgeon.
Physical characteristics and simulated transport of pallid sturgeon and shovelnose sturgeon eggs
The imperiled pallid sturgeon (Scaphirhynchus albus) and closely related, but more common, shovelnose sturgeon (S. platorynchus) are believed to broadcast adhesive, demersal eggs in the current and over coarse substrate in turbid rivers of the North American midcontinent. It has been hypothesized that eggs settle immediately following...
Chojnacki, Kimberly; Erwin, Susannah O.; George, Amy E.; Candrl, James; Jacobson, Robert B.; Delonay, Aaron J. Evaluating flow management as a strategy to recover an endangered sturgeon species in the Upper Missouri River, USA
In the Upper Missouri River, Fort Peck and Garrison Dams limit the length of free‐flowing river available to the endangered pallid sturgeon. These barriers restrict the upstream migration of adults and downstream larval dispersal. A one‐dimensional (1D) modelling framework is currently in use to evaluate reservoir operation alternatives and to...
Erwin, Susannah O.; Bulliner, Edward A.; Fischenich, Craig J; Jacobson, Robert B.; Braaten, Patrick; Delonay, Aaron J. Status of knowledge of the Pallid Sturgeon (Scaphirhynchus albus Forbes and Richardson, 1905)
The Pallid Sturgeon is listed as federally endangered under the Endangered Species Act in the United States. When the species was listed in 1990 it was considered extremely rare and was poorly understood. Habitat alteration, commercial harvest, environmental contaminants, and other factors were identified as threats. Today our scientific...
Jordan, G. R.; Heist, E.J.; Braaten, Patrick; Delonay, Aaron J.; Hartfield, P.; Herzog, D.P.; Kappenman, K.M.; Web, M.A.H. Identifying sturgeon spawning locations through back-calculations of drift
Unfavorable spawning habitat conditions have been identified as a potential limiting factor for recovery of the endangered pallid sturgeon on the Missouri River and its tributaries. After successful spawning, incubation, and hatching, sturgeon free embryos passively drift downstream and are sometimes captured by sampling crews. While spawning...
Bulliner, Edward A.; Erwin, Susannah O.; Jacobson, Robert B.; Chojnacki, Kimberly A.; George, Amy E.; Delonay, Aaron J.
Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River—Annual report 2014
The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of sturgeon reproductive ecology, early life history, habitat...
Delonay, Aaron J.; Chojnacki, Kimberly A.; Jacobson, Robert B.; Braaten, Patrick J.; Buhl, Kevin J.; Elliott, Caroline M.; Erwin, Susannah O.; Faulkner, Jacob D.A.; Candrl, James S.; Fuller, David B.; Backes, Kenneth M.; Haddix, Tyler M.; Rugg, Matthew L.; Wesolek, Christopher J.; Eder, Brandon L.; Mestl, Gerald E.
Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River—Annual report 2013
The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of pallid sturgeon reproductive ecology, early life history, habitat...
Delonay, Aaron J.; Jacobson, Robert B.; Chojnacki, Kimberly A.; Braaten, Patrick J.; Buhl, Kevin J.; Eder, Brandon L; Elliott, Caroline M.; Erwin, Susannah O.; Fuller, David B.; Haddix, Tyler M.; Ladd, Hallie L.A.; Mestl, Gerald E.; Papoulias, Diana M.; Rhoten, Jason C.; Wesolek, Christopher J.; Wildhaber, Mark L.
Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River—A synthesis of science, 2005 to 2012
This report is intended to synthesize the state of the scientific understanding of pallid sturgeon ecological requirements to provide recommendations for future science directions and context for Missouri River restoration and management decisions. Recruitment of pallid sturgeon has been low to non-existent throughout its range. Emerging...
Delonay, Aaron J.; Chojnacki, Kimberly A.; Jacobson, Robert B.; Albers, Janice L.; Braaten, Patrick J.; Bulliner, Edward A.; Elliott, Caroline M.; Erwin, Susannah O.; Fuller, David B; Haas, Justin D.; Ladd, Hallie L.A.; Mestl, Gerald E.; Papoulias, Diana M.; Wildhaber, Mark L.
Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River: annual report 2011
The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of sturgeon reproductive ecology, early life history, habitat...
DeLonay, Aaron J.; Jacobson, Robert B.; Chojnacki, Kimberly A.; Annis, Mandy L.; Braaten, P. J.; Elliott, Caroline M.; Fuller, D. B.; Haas, Justin D.; Haddix, Tyler M.; Ladd, Hallie L.A.; McElroy, Brandon J.; Mestl, Gerald E.; Papoulias, Diana M.; Rhoten, Jason C.; Wildhaber, Mark L. Gonadosomatic index and fecundity of Lower Missouri and Middle Mississippi River endangered pallid sturgeon estimated using minimally invasive techniques
Minimally invasive, non-lethal methods of ultrasonography were used to assess sex, egg diameter, fecundity, gonad volume, and gonadosomatic index, as well as endoscopy to visually assess the reproductive stage of Scaphirhynchus albus. Estimated mean egg diameters of 2.202 ± 0.187 mm and mean fecundity of 44 531 ± 23...
Albers, J.L.; Wildhaber, M.L.; DeLonay, A.J. Optimum swimming pathways of fish spawning migrations in rivers
Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this...
McElroy, Brandon; DeLonay, Aaron; Jacobson, Robert
Ecological requirements for pallid sturgeon reproduction and recruitment in the Lower Missouri River: Annual report 2010
The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of sturgeon reproductive ecology, early life history, habitat...
DeLonay, Aaron J.; Jacobson, Robert B.; Papoulias, Diana M.; Wildhaber, Mark L.; Chojnacki, Kimberly A.; Pherigo, Emily K.; Haas, Justin D.; Mestl, Gerald E. Identifying structural elements needed for development of a predictive life-history model for pallid and shovelnose sturgeons
Intensive management of the Missouri and Mississippi Rivers has resulted in dramatic changes to the river systems and their biota. These changes have been implicated in the decline of the pallid sturgeon (Scaphirhynchus albus), which has been listed as a United States federal endangered species. The sympatric shovelnose sturgeon (S. ...
Wildhaber, Mark L.; DeLonay, A.J.; Papoulias, D.M.; Galat, D.L.; Jacobson, R.B.; Simpkins, D.G.; Braaten, P.J.; Korschgen, C. E.; Mac, M.J.
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New Evidence Shows Endangered Pallid Sturgeon Spawned in Lower Missouri River
Three tiny fish larvae that were captured by U.S. Geological Survey scientists in May 2014 have just been confirmed to be pallid sturgeon. These new genetic identifications add to mounting evidence that critically endangered pallid sturgeon spawned successfully in the Lower Missouri River downstream of Gavins Point Dam, South Dakota.